TY  - BOOK
AU  - Hellwig,Günter
TI  - Differential operators of mathematical physics: an introduction 
T2  - Addison-Wesley series in mathematics
U1  - 517.7 
PY  - 1967///
CY  - Reading, Mass.
PB  - Addison-Wesley Pub. Co.
KW  - Differential equations, Partial
KW  - Hilbert space
KW  - Mathematical physics
N1  - Includes index; Bibliography: p. 289-293
ER  -